Role of Electrolytes in Electrochemical Properties of La2SrV2O9–rGO Composite as Electrode Material

Abstract

The rising need to store energy intermittently offers excellent opportunities for supercapacitors with high potential storage capabilities. In this work, we explore the La2SrV2O9–rGO composite material for supercapacitor application. The crystallographic properties, morphological, optical, and electrochemical properties of La2SrV2O9–rGO composite and bare La2SrV2O9 prepared via chemical precipitation method are investigated to estimate their potential for energy storage. We further illustrate the unique role of rGO towards the variations in capacitance, by varying the different electrolyte solutions such as H2SO4 and NaOH. Cyclic voltammetry studies reveal the quasi-rectangular profiles which confirm the electrochemical double layer and Faradic capacitance behaviours upon employing both electrolytes. The capacitance of La2SrV2O9–rGO in acidic and alkaline environment are 428.12 and 212.6, similarly for La2SrV2O9 in acidic and alkaline are 380.6 and 324.6 F g−1 respectively. Specific capacitance calculated using current density and obtained 450 F g−1 and 47 F g−1 at 0.5 A g−1 for La2SrV2O9–rGO in acidic and alkaline electrolyte. H2SO4 is a strong electrolyte, it donates protons and ionises completely. As the result, capacitance increases for acidic electrolyte while it decreases for alkaline electrolyte. Our results emphasize the role of electrolyte interaction with La2SrV2O9 and La2SrV2O9–rGO to achieve better capacitance values. The obtained results found to be promising in the development of La2SrV2O9 with rGO as suitable electrode material for supercapacitor applications.